1. Technical Field
The present invention generally relates to safety restraints for motor vehicles. More particularly, the present invention relates to an energy absorbing seat belt mounting arrangement.
2. Discussion
Vehicle occupant restraint systems having a seat belt webbing and a guide for guiding the seat belt webbing are well known. In many known occupant restraint systems, a seat belt webbing guide is attached to the vehicle B-pillar. The seat belt webbing guide, which is commonly referred to as a D-ring, assists in positioning a shoulder belt portion of the seat belt diagonally across an occupant. In many applications, the D-ring is vertically adjustable to facilitate proper location of the shoulder belt portion.
Federal Motor Vehicle Safety Standard (FMVSS) requirements scheduled for gradual introduction beginning with the 1999 model year specify maximum HIC (head injury criteria) for various points along the vehicle B-pillar. In testing, the head of an anthropomorphic test device (ATD or test dummy) is impacted with the B-pillar at a predetermined speed at each of the various points. The HIC from the impact is derived with data obtained from a tri-axial accelerometer located on the ATD head.
One of the specific points on the B-pillar which must satisfy the FMVSS is the D-ring anchorage. The entire length of the anchorage must satisfy pertinent requirements. Targets can be located on decorative trim covering the anchorage or a portion of the anchorage.
A common technique for absorbing energy within vehicle occupant compartments is through the addition of foam, such as polystyrene or the like. While often desirable for certain applications, foam energy absorbers are associated with disadvantages. For example, foam energy absorbers intrude into the vehicle interior. Further, foam energy absorbers are not suitable for anchorage points. Thus, it is desirable to provide an improved mounting structure for a seat belt which absorbs energy.